Objective To characterize the immunogenicity in gene immunization of the conserved regions of hepatitis C virus(HCV) based on different delivery strategies. Methods We first constructed a novel DNA vaccine encoding a fusion gene(from partial NS3 and Core) of HCV. Then we compared different protocols based on naked DNA injection twice or DNA injection with gene electrotransfer(GET) in BALB/c mice. The immune response was measured by antibody ELISA and by IFN-gamma ELISPOT. Results Our data showed that a protocol based on intradermally injection of DNA with optimal GET induced the strongest humoral and cellular immunity, and DNA with GET induced a substantially higher anti-NS3/Core T cell re-spoase than naked DNA injection. Conclusion Our data suggest that DNA vaccines encoding NS3/Core fu-sion protein of HCV immunized by the present strategy could merit further study in the context of future prophylactic and therapeutic HCV T cell based vaccines.

BACKGROUNDTo determine the antigenicity of HGV NS5 recombinant proteins expressed in E.coli.

METHODSHGV NS5a,NS5b and core/NS5b fusion genes were cloned into pThioC vector. Three expression plasmids were transformed into JM109(DE3) competent cells then expressed with induction by IPTG. Western blot and ELISA were used to determine the antigenicity after the three recombinant proteins were purified.

RESULTSAfter identification by restriction enzyme and sequencing, it was confirmed that the expressed was target proteins espected. Purified expression proteins were found strongly immunoreactive among anti HGV positive sera by Western blot and ELISA. Compared with mixed recombinant antigen (including core, NS5a synthetic peptide and NS3 recombinant proteins), in the 22 positive sera detected with mixed antigen, 68%(15/22), 90%(20/22) and 73%(16/22) were positive by P5a,P5b and Pc?5b antigens; In the 70 negative samples with mixed antigen, 7%(5/70), 1%(1/70) and 6%(4/70) were positive by P5a, P5b and Pc?5b antigens. The positive alone was found among RTPCR positive specimen using these recombinant antigens.

CONCLUSIONSNS5 gene expressed in E.coli?which couldn't be covered with other regions of antigens was one of the essential epitopes to HGV immunologic diagnosis.

Antibodies, Viral ; blood ; Antigens, Viral ; blood ; Epitopes ; immunology ; GB virus C ; genetics ; immunology ; Humans ; Plasmids ; genetics ; Recombinant Proteins ; biosynthesis ; immunology ; Viral Nonstructural Proteins ; genetics ; immunology

Objective: To prepare peptide minotope-based recombinant diagnostic antigen of Epstein-Barr virus (EBV) infection and evaluate its antigenicity preliminarily. Methods: With Trx at the N-terminal and His tag at the C-terminal, the peptide minotope of EBV (GP125, F1, A2, A3C2) was expressed in Escherichia coli and purified by affinity and anion exchange chromatography (designated 'H58’); based on antigenicity of H58 identified by Western blotting (WB), we constructed and evaluated a novel early diagnostic ELISA for EBV infection. Results: The soluble H58 protein with high concentration (2.8 mg/ml) and purity (99.01) was obtained; WB analysis found that there was an obvious band (28 ×10³) on the NC membrane, using H58 anti-Trx monoclonal antibody or acute-phase sera of EBV infection as the first antibody. With the novel ELISA, 50 positive sera of EBV infection and 50 negative sera were detected, displaying that the grouping of OD value of positive serum (95%CI: 1.233-1.489) and negative serum (95%CI: 0.113-0.159) was different (P<0.05) with the sensitivity 98.0%, specificity 96.0% and kappa value 0.940. Conclusions By E. coli expression and affinity and ion exchange chromatography purification, the peptide minotope-based recombinant diagnostic antigen of EBV infection was obtained with excellent antigenicity, which could be applied for serological detection of EBV infection.